Method and apparatus to measure motion characteristics for bicycles and any vehicles on wheels

Abstract

A sensor system for use with a host device a vehicle having a frame and at least one wheel. The sensor system has a first sensor associated with the at least one wheel of the vehicle. The first sensor generates wheel data indicative of movement of the wheel. The wheel data may be rotational angle, full revolution count, angle of a revolution, direction of revolution, and angular acceleration with respect to a magnetic pole of the Earth or a magnet attached to a frame. The sensor transmits the wheel data to the host device.

What is claimed is: 
     
       1. A sensor system for use with a host device and a vehicle comprising a frame and at least one wheel, the sensor system comprising:
 a first sensor associated with the at least one wheel of the vehicle, where the first sensor is configured to sense raw wheel data indicative of a rotational movement of the at least one wheel, the raw wheel data being sensed with respect to one of: a magnetic pole of the Earth or a magnet attached to the frame; 
 a microcontroller configured to
 detect, during the rotational movement of the at least one wheel, changes in the raw wheel data; and 
 determine, based on the changes in the raw wheel data, wheel data, the wheel data including a rotational angle of the at least one wheel, a full revolution count of the at least one wheel an angle of a revolution of the at least one wheel, a rotational direction of the revolution of the at least one wheel, and an angular acceleration of the at least one wheel; and 
 
 a transmitter configured to transmit the wheel data to the host device. 
 
     
     
       2. A sensor system as recited in  claim 1 , further comprising a second sensor associated with the frame of the vehicle, where the second sensor:
 senses frame data, the frame data including at least one of: a grade of an angle of travelling surface relative to horizon in per cent, a direction of gravity, a cadence, a lateral leaning angle, and a frequency of change for lateral leaning from left to right indicative of movement of the frame with respect to the direction of gravity; and 
 wherein the transmitter is further configured to transmit the frame data to the host device. 
 
     
     
       3. A sensor system as recited in  claim 1 , further comprising a communications system for wirelessly transmitting data between the host device and the first sensor and between the host device and the second sensor. 
     
     
       4. A sensor system as recited in  claim 1 , in which the first sensor comprises a magnetometer. 
     
     
       5. A sensor system as recited in  claim 2 , in which the second sensor comprises an accelerometer. 
     
     
       6. A sensor system as recited in  claim 2 , in which:
 the first sensor comprises a magnetometer; and 
 the second sensor comprises an accelerometer. 
 
     
     
       7. A sensor system as recited in  claim 6 , in which:
 the first sensor senses the raw wheel data based on raw magnetic field data generated by the magnetometer; and 
 the second sensor senses the frame data based on raw acceleration data generated by the accelerometer. 
 
     
     
       8. A sensor system as recited in  claim 2 , in which:
 the first sensor comprises
 a magnetometer; 
 and 
 
 the second sensor comprises
 an accelerometer, and 
 a gyroscope. 
 
 
     
     
       9. A sensor system as recited in  claim 2 , in which:
 the host device is configured to determine, based on the wheel data, at least one of, a speed of the vehicle, a distance traveled by the vehicle, and a linear acceleration of the at least one wheel; and 
 the frame data further includes at least one of an angle of the frame with respect to horizontal and lateral motion of the frame. 
 
     
     
       10. A sensor system as recited in  claim 1 , wherein:
 the microcontroller configured to:
 store calibration data indicative of the rotational movement of the at least one wheel, wherein the calibration data are generated from raw wheel data generated during rotation of the at least one wheel at a substantially even rate of the rotation; and 
 determine, based on the raw wheel data and the calibration data, the wheel data. 
 
 
     
     
       11. A sensor system as recited in  claim 2 , in which the second sensor stores frame calibration data generated from the frame data associated with two angular positions of the frame with respect to the direction of gravity, where the frame data is calibrated using the frame calibration data. 
     
     
       12. A sensing method for use with a host device and a vehicle comprising a frame and at least one wheel, the method comprising the steps of:
 associating a first sensor with the at least one wheel of the vehicle; 
 sensing, by the first sensor, raw wheel data indicative of a rotational movement of the at least one wheel, the raw data being sensed with respect to one of: a magnetic pole of the Earth or a magnet attached to the frame; 
 during the rotational movement of the at least one wheel, detecting, by a microcontroller, changes in the raw wheel data; 
 determining, by the microcontroller, based on the changes in the raw wheel data, wheel data, the wheel data including a rotational angle of the at least one wheel, a full revolution count of the at least one wheel, an angle of a revolution of the at least one wheel, a direction of the revolution of the at least one wheel, and an angular acceleration of the at least one wheel; and 
 transmitting, by a transmitter, the wheel data to the host device. 
 
     
     
       13. A sensing method as recited in  claim 12 , further comprising the steps of:
 associating a second sensor with the frame of the vehicle; and 
 sensing by the second sensor, frame data indicative of a movement of the frame with respect to a direction of gravity; and 
 transmitting, by the transmitter, the frame data to the host device. 
 
     
     
       14. A sensing method as recited in  claim 13 , further comprising the steps of:
 wirelessly transmitting the wheel data from the first sensor to the host device; and 
 wirelessly transmitting the frame data from the second sensor to the host device. 
 
     
     
       15. A sensing method as recited in  claim 13 , in which:
 the step of sensing the wheel data comprises sensing the wheel data based on raw magnetic field data generated by a magnetometer; and 
 the step of sensing the frame data comprises sensing the frame data based on raw acceleration data generated by the accelerometer. 
 
     
     
       16. A sensing method as recited in  claim 13 , further comprising the steps of:
 determining at least one of an angle of rotation of the at least one wheel, a rotational direction of the at least one wheel, speed of the vehicle, a distance traveled by the vehicle, and an acceleration of the at least one wheel based on the wheel data; and 
 determining at least one of an angle of the frame with respect to horizontal and lateral motion of the frame based on the frame data. 
 
     
     
       17. A sensing method as recited in  claim 12 , further comprising:
 storing, by the microcontroller, calibration data indicative of the rotational movement of the at least one wheel, wherein the calibration data are generated from raw wheel data generated during rotation of the at least one wheel at a substantially even rate of the rotation; and 
 determining, by the microcontroller, based on the raw wheel data and the calibration data, the wheel data. 
 
     
     
       18. A sensing method as recited in  claim 13 , further comprising the steps of:
 generating frame calibration data from the frame data associated with two angular positions of the frame with respect to the direction of gravity; and 
 calibrating the frame data based on the frame calibration data. 
 
     
     
       19. A sensor system for use with a host device a vehicle comprising a frame and at least one wheel, the sensor system comprising:
 a first sensor associated with the at least one wheel of the vehicle, where the first sensor comprises a first magnetometer; and 
 a second sensor associated with the frame of the vehicle, where the second sensor comprises a second accelerometer and a second gyroscope; 
 wherein the first sensor is configured to sense raw wheel data indicative of a rotational movement of the at least one wheel, the raw data being sensed with respect to one of: a magnetic pole of the Earth or a magnet attached to the frame, the raw wheel data being sensed based on raw data generated by at least one of the first magnetometer; 
 wherein the second sensor is configured to sense frame data indicative of a movement of the frame with respect to a direction of gravity, the frame data being sensed based on raw data sensed by at least one of the second accelerometer and the second gyroscope; 
 a microcontroller configured to:
 detect, during the rotational movement of the at least one wheel, changes in the raw wheel data; and 
 determine, based on the changes in the raw wheel data, wheel data, the wheel data including a rotational angle of the at least one wheel, a full revolution count of the at least one wheel, an angle of a revolution of the at least one wheel, a direction of the revolution of the at least one wheel, and an angular acceleration of the at least one wheel; and 
 
 a transmitter configured to transmit the wheel data and the frame data to the host device. 
 
     
     
       20. A sensor system as recited in  claim 19 , wherein
 the second sensor further comprises:
 a second microcontroller for generating the frame data based on the raw data generated by at least one of the second accelerometer and the second gyroscope, and 
 a second transmitter for transmitting the frame data to the host device. 
 
 
     
     
       21. A sensor system as recited in  claim 19 , in which:
 the wheel data further includes at least one of a rotational direction of the at least one wheel, a speed of the vehicle, a distance traveled by the vehicle, and a linear acceleration of the at least one wheel; and 
 the frame data further includes at least one of an angle of the frame with respect to horizontal and lateral motion of the frame. 
 
     
     
       22. A sensor system as recited in  claim 19 , wherein the microcontroller configured to:
 store calibration data indicative of the rotational movement of the at least one wheel, wherein the calibration data are generated from raw wheel data generated during rotation of the at least one wheel at a substantially even rate of the rotation; and 
 determine, based on the changes in the raw wheel data, wheel data, the wheel data. 
 
     
     
       23. A sensor system as recited in  claim 19 , in which the second sensor stores frame calibration data generated from the frame data associated with two angular positions of the frame with respect to the direction of gravity, where the frame data is calibrated using the frame calibration data. 
     
     
       24. A sensor system as recited in  claim 20 , in which:
 the first MCU stores wheel calibration data generated from raw wheel data generated during free rotation of the at least one wheel, where the wheel data is calibrated using the wheel calibration data; and 
 the second MCU stores frame calibration data generated from raw frame data associated with two angular positions of the frame with respect to the direction of gravity, where the frame data is calibrated using the frame calibration data.